1. Field of the Invention
The present invention is generally related to processes and systems for recovering a liquid natural gas (“LNG”) from a hydrocarbon-containing gas. More particularly, the present invention is generally related to processes and systems for recovering a LNG from a synthesis gas using a single closed-loop mixed refrigerant cycle.
2. Description of the Related Art
Synthesis gas, which is also known as “syngas,” is a common byproduct formed during steam reforming of natural gas or hydrocarbons, coal gasification, and waste-to-energy gasification. Syngas generally contains varying amounts of carbon monoxide and hydrogen and, in some circumstances, can also contain notable amounts of methane. Due to the commercial value of methane, it can be desirable in some cases to remove at least a portion of the methane from syngas. However, the presence of carbon monoxide and hydrogen in these gases can greatly reduce the efficiencies of conventional recovery processes since these processes are generally unable to fully condense and separate the carbon monoxide and hydrogen from the methane at the recovery temperatures commonly used during these various processes. Thus, the recovered methane can be contaminated with high levels of residual carbon monoxide and/or hydrogen. Consequently, the presence of carbon monoxide and hydrogen in syngas and other hydrocarbon-containing gases can negatively impact the recovery of methane from these gases.
Therefore, there is a need for processes and systems that can effectively recover methane from syngas and other hydrocarbon-containing gases despite the presence of carbon monoxide and hydrogen in these gases.